# Writing Code > Write code to implement features or fix issues. Use when this capability is needed. - Skill: `tomevault-io/writing-code` (Agent Skill, multi-file: 2 files) - Install (CLI): `npx skillmds@latest add tomevault-io/writing-code` - Raw SKILL.md: https://api.skillmd.com/api/skills/tomevault-io/writing-code/raw - Safety review: pending (external: skill-scanner PASS, skillspector PASS) - Works with: Claude Code, Claude.ai, OpenAI Codex - Category: Coding & Dev Tools - Author: tomevault-io (https://skillmd.com/u/tomevault-io) - Updated: 2026-09-17 - Page: https://skillmd.com/skills/tomevault-io/writing-code --- # Writing Code - check for backwards compatibility if function is public and existed before the git branch was created - Use test driven development, write tests first, then write code to pass the tests - use `black` to format code. - prefer to re-use/modifying existing functions over writing new functions, check codebase for existing solutions --- > Converted and distributed by [TomeVault](https://tomevault.io/claim/neurostuff) — claim your Tome and manage your conversions.